Deep sea pH sensor

Abstract

Systems and methods are provided for a deep sea pH sensor. In one embodiment, a method for manufacturing a pH sensor comprises forming a sensor electrode in a working surface of a die wherein the sensor electrode is able to sense the pH of a liquid and forming at least one isolation groove around the sensor electrode on the working surface of the die, wherein the die has a wide street around the sensor electrode and the at least one isolation groove. The method further comprises mounting the die onto a base and securing a seal on the working surface in the wide street, wherein the seal surrounds the isolation groove, the seal sealing the liquid within the portion of the working surface of the die containing the sensor electrode and the isolation groove, when the pH sensor is subjected to high pressure.

What is claimed is: 
     
       1. A pH sensor, comprising:
 a base; 
 a sensor electrode formed on a working surface of a die, wherein the die is mounted to the base, wherein the sensor electrode is configured to sense the pH of a liquid when in contact with the liquid; 
 a high pressure seal in contact with the working surface, the high pressure seal configured to isolate liquid to the working surface of the die when the pH sensor is subjected to high pressure; and 
 at least one isolation groove formed around the sensor electrode on the working surface of the die, wherein the at least one isolation groove is configured to isolate the sensor electrode from stress produced by the high pressure seal on the working surface when the pH sensor is subjected to high pressure. 
 
     
     
       2. The pH sensor of  claim 1 , wherein the high pressure seal comprises:
 an O-ring in contact with the working surface of the die, wherein the O-ring encircles the at least one isolation groove; and 
 a sealing cover configured to secure the O-ring on the extended surface area when the pH sensor is subjected to high pressure. 
 
     
     
       3. The pH sensor of  claim 2 , wherein the O-ring is mounted on an extended portion of the die that extends around the at least one isolation groove on the surface of the die. 
     
     
       4. The pH sensor of  claim 2 , wherein the sensor electrode is less than 0.16 inches across at a widest portion and the diameter of the O-ring is at least 0.16 inches. 
     
     
       5. The pH sensor of  claim 1 , further comprising a pump configured to force the liquid to continuously flow across the sensor electrode. 
     
     
       6. The pH sensor of  claim 5 , wherein the pump is configured as at least one of a:
 a push pump; and 
 a pull pump. 
 
     
     
       7. The pH sensor of  claim 1 , wherein the die is mounted to the base using a bonding layer. 
     
     
       8. The pH sensor of  claim 7 , wherein the sensor electrode is electrically connected to wirebonds on the base that are embedded in the bonding layer. 
     
     
       9. The pH sensor of  claim 7 , wherein the bonding layer is composed of frit. 
     
     
       10. A method for manufacturing a pH sensor, the method comprising:
 forming a sensor electrode in a working surface of a die wherein the sensor electrode is able to sense the pH of a liquid; 
 forming at least one isolation groove around the sensor electrode on the working surface of the die, wherein the die has a wide street around the sensor electrode and the at least one isolation groove; 
 mounting the die onto a base; and 
 securing a seal on the working surface in the wide street, wherein the seal surrounds the isolation groove, the seal sealing the liquid within the portion of the working surface of the die containing the sensor electrode and the isolation groove, when the pH sensor is subjected to high pressure. 
 
     
     
       11. The method of  claim 10 , wherein forming the sensor electrode comprises
 forming the sensor electrode on a wafer containing a plurality of sensor electrodes; and 
 singulating the wafer to form the die including the sensor electrode. 
 
     
     
       12. The method of  claim 10 , wherein the die is mounted to the base using a frit layer. 
     
     
       13. The method of  claim 10 , wherein the seal is at least one of:
 at least one O-ring held in place by a pressure containment cover; and 
 an epoxy that secures the pressure containment cover to the working surface of the die. 
 
     
     
       14. The method of  claim 13 , wherein the O-ring encircles the at least one isolation groove and the sensor electrode. 
     
     
       15. A pH sensing device, the device comprising:
 a base; 
 a die containing a sensor electrode formed on a working surface of the die, the die mounted to the base, wherein the sensor electrode is configured to sense the pH of a liquid when in contact with the liquid; 
 an O-ring placed on the working surface of the die, the O-ring encircling the sensor electrode, wherein the O-ring has a diameter that is substantially large such that liquid can flow freely across the sensor electrode; 
 a pressure containment cover configured to secure the O-ring on the working surface, such that the pressure containment cover and the O-ring configured to seal liquid that contacts the sensor electrode from the area of the working surface that is outside the inner diameter of the O-ring when the pH sensing device is subjected to high pressure; and 
 a flow mechanism configured to force a fluid to continuously flow across the sensor electrode. 
 
     
     
       16. The pH sensing device of  claim 15 , wherein the portion of the die on the working surface that is outside the inner diameter of the O-ring is blank. 
     
     
       17. The pH sensing device of  claim 15 , wherein the flow mechanism is a pump attached to the pressure containment cover. 
     
     
       18. The pH sensing device of  claim 15 , wherein the pH sensing device is mounted on a buoy in a body of water, the buoy configured to submerge in the water to depths up to 7 miles. 
     
     
       19. The pH sensing device of  claim 18 , wherein the pH sensing device incrementally gathers pH measurements as the buoy travels from a bottom of the body of water to a surface of the body of water. 
     
     
       20. The pH sensing device of  claim 19 , wherein the buoy transmits the pH measurements to data gathering system when the buoy is on the surface of the body of water.